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At least 55 records · Page 3

Multifunctional Cooling Garment for Space Suit Environmental Control

Future manned space exploration missions will require space suits with capabilities beyond the current state of the art. Portable Life Support Systems for these future space suits face daunting challenges, since they must maintain healthy and comfortable conditions inside the suit for longduration missions while minimizing weight and water venting. We have demonstrated the feasibility of an innovative, multipurpose garment for thermal and humidity control inside a space suit pressure garment that is simple, rugged, compact, and lightweight. The garment is a based on a conventional liquid cooling and ventilation garment (LCVG) that has been modified to directly absorb latent heat as well as sensible heat. This hybrid garment will prevent buildup of condensation inside the pressure garment, prevent loss of water by absorption in regenerable CO2 removal beds, and conserve water through use of advanced lithium chloride absorber/radiator (LCAR) technology for nonventing heat rejection. We have shown the feasibility of this approach by sizing the critical components for the hybrid garment, developing fabrication methods, building and testing a proof-of-concept system, and demonstrating by test that its performance is suitable for use in space suit life support systems.

Izenson, Michael G.↗

A methodology for choosing candidate materials for the fabrication of planetary space suit structures

A study of space suit structures and materials is under way at NASA Ames Research Center, Moffett Field, CA. The study was initiated by the need for a generation of lightweight space suits to be used in future planetary Exploration Missions. This paper provides a brief description of the Lunar and Mars environments and reviews what has been done in the past in the design and development of fabric, metal, and composite suit components in order to establish criteria for comparison of promising candidate materials and space suit structures. Environmental factors and mission scenarios will present challenging material and structural requirements; thus, a program is planned to outline the methodology used to identify materials and processes for producing candidate space suit structures which meet those requirements.

Jacobs, Gilda↗

Multifunctional Cooling Garment for Space Suit Environmental Control

Future manned space exploration missions will require space suits with capabilities beyond the current state of the art. Portable Life Support Systems for these future space suits face daunting challenges, since they must maintain healthy and comfortable conditions inside the suit for long-duration missions while minimizing weight and water venting. We have demonstrated the feasibility of an innovative, multipurpose garment for thermal and humidity control inside a space suit pressure garment that is simple, rugged, compact, and lightweight. The garment is a based on a conventional liquid cooling and ventilation garment (LCVG) that has been modified to directly absorb latent heat as well as sensible heat. This hybrid garment will prevent buildup of condensation inside the pressure garment, prevent loss of water by absorption in regenerable CO2 removal beds, and conserve water through use of advanced lithium chloride absorber/radiator (LCAR) technology for nonventing heat rejection. We have shown the feasibility of this approach by sizing the critical components for the hybrid garment, developing fabrication methods, building and testing a proof-of-concept system, and demonstrating by test that its performance is suitable for use in space suit life support systems.

Izenson, Michael↗

CO2 Washout Testing Using Various Inlet Vent Configurations in the Mark-III Space Suit

Requirements for using a space suit during ground testing include providing adequate carbon dioxide (CO2) washout for the suited subject. Acute CO2 exposure can lead to symptoms including headache, dyspnea, lethargy and eventually unconsciousness or even death. Symptoms depend on several factors including inspired partial pressure of CO2 (ppCO2), duration of exposure, metabolic rate of the subject and physiological differences between subjects. Computational Fluid Dynamic (CFD) analysis has predicted that the configuration of the suit inlet vent has a significant effect on oronasal CO2 concentrations. The main objective of this test is to characterize inspired oronasal ppCO2 for a variety of inlet vent configurations in the Mark-III space suit across a range of workload and flow rates. As a secondary objective, results will be compared to the predicted CO2 concentrations and used to refine existing CFD models. These CFD models will then be used to help design an inlet vent configuration for the Z-2 space suit, which maximizes oronasal CO2 washout. This test has not been completed, but is planned for January 2014. The results of this test will be incorporated into this paper. The testing methodology used in this test builds upon past CO2 washout testing performed on the Z-1 suit, Rear Entry I-Suit (REI) and the Enhanced Mobility Advanced Crew Escape Suit (EM-ACES). Three subjects will be tested in the Mark-III space suit with each subject performing two test sessions to allow for comparison between tests. Six different helmet inlet vent configurations will be evaluated during each test session. Suit pressure will be maintained at 4.3 psid. Subjects will wear the suit while walking on a treadmill to generate metabolic workloads of approximately 2000 and 3000 BTU/hr. Supply airflow rates of 6 and 4 actual cubic feet per minute (ACFM) will be tested at each workload. Subjects will wear an oronasal mask with an open port in front of the mouth and will be allowed to breathe freely. Oronasal ppCO2 will be monitored real-time via gas analyzers with sampling tubes connected to the oronasal mask. Metabolic rate will be calculated from the total oxygen consumption and CO2 production measured by additional gas analyzers at the air outlet from the suit. Real-time metabolic rate measurements will be used to adjust the treadmill workload to meet target metabolic rates. This paper provides detailed descriptions of the test hardware, methodology and results, as well as implications for future inlet vent design and ground testing in the Mark-III.

Korona, F. Adam↗

Skin microvascular flow during hypobaric exposure with and without a mechanical counter-pressure space suit glove

INTRODUCTION: Current space suits are rigid, gas-pressurized shells that protect astronauts from the vacuum of space. A tight elastic garment or mechanical-counter-pressure (MCP) suit generates pressure by compression and may have several advantages over current space suit technology. In this study, we investigated local microcirculatory effects produced with and without a prototype MCP glove. METHODS: The right hand of eight normal volunteers was studied at normal ambient pressure and during exposure to -50, -100 and -150 mm Hg with and without the MCP glove. Measurements included the pressure against the hand, skin microvascular flow, temperature on the dorsum of the hand, and middle finger girth. RESULTS: Without the glove, skin microvascular flow and finger girth significantly increased with negative pressure, and the skin temperature decreased compared with the control condition. The MCP glove generated approximately 200 mm Hg at the skin surface; all measured values remained at control levels during exposure to negative pressure. DISCUSSION: Without the glove, skin microvascular flow and finger girth increased with negative pressure, probably due to a blood shift toward the hand. The elastic compression of the material of the MCP glove generated pressure on the hand similar to that in current gas-pressurized space suit gloves. The MCP glove prevented the apparent blood shift and thus maintained baseline values of the measured variables despite exposure of the hand to negative pressure.

NASA Discipline Cardiopulmonary↗

Z-1 Prototype Space Suit Testing Summary

The Advanced Space Suit team of the NASA-Johnson Space Center performed a series of test with the Z-1 prototype space suit in 2012. This paper discusses, at a summary level, the tests performed and results from those tests. The purpose of the tests were two -fold: 1) characterize the suit performance so that the data could be used in the downselection of components for the Z -2 Space Suit and 2) develop interfaces with the suitport and exploration vehicles through pressurized suit evaluations. Tests performed included isolated and functional range of motion data capture, Z-1 waist and hip testing, joint torque testing, CO2 washout testing, fit checks and subject familiarizations, an exploration vehicle aft deck and suitport controls interface evaluation, delta pressure suitport tests including pressurized suit don and doff, and gross mobility and suitport ingress and egress demonstrations in reduced gravity. Lessons learned specific to the Z -1 prototype and to suit testing techniques will be presented.

Ross, Amy J.↗

Z-1 Prototype Space Suit Testing Summary

The Advanced Space Suit team of the NASA-Johnson Space Center performed a series of test with the Z-1 prototype space suit in 2012. This paper discusses, at a summary level, the tests performed and results from those tests. The purpose of the tests were two-fold: 1) characterize the suit performance so that the data could be used in the downselection of components for the Z-2 Space Suit and 2) develop interfaces with the suitport and exploration vehicles through pressurized suit evaluations. Tests performed included isolated and functional range of motion data capture, Z-1 waist and hip testing, joint torque testing, CO2 washout testing, fit checks and subject familiarizations, an exploration vehicle aft deck and suitport controls interface evaluation, delta pressure suitport tests including pressurized suit don and doff, and gross mobility and suitport ingress and egress demonstrations in reduced gravity. Lessons learned specific to the Z-1 prototype and to suit testing techniques will be presented.

Ross, Amy↗

Shuttle Space Suit: Fabric/LCVG Model Validation

A detailed space suit computational model is being developed at the Langley Research Center for radiation exposure evaluation studies. The details of the construction of the space suit are critical to estimation of exposures and assessing the risk to the astronaut on EVA. Past evaluations of space suit shielding properties assumed the basic fabric layup (Thermal Micrometeoroid Garment, fabric restraints, and pressure envelope) and LCVG could be homogenized as a single layer overestimating the protective properties over 60 percent of the fabric area. The present space suit model represents the inhomogeneous distributions of LCVG materials (mainly the water filled cooling tubes). An experimental test is performed using a 34-MeV proton beam and high-resolution detectors to compare with model-predicted transmission factors. Some suggestions are made on possible improved construction methods to improve the space suit s protection properties.

Wilson, J. W.↗

CO2 Washout Testing of the REI and EM-ACES Space Suits

When a space suit is used during ground testing, adequate carbon dioxide (CO2) washout must be provided for the suited subject. Symptoms of acute CO2 exposure depend on partial pressure of CO2 (ppCO2), metabolic rate of the subject, and other factors. This test was done to characterize inspired oronasal ppCO2 in the Rear Entry I-Suit (REI) and the Enhanced Mobility Advanced Crew Escape Suit (EM-ACES) for a range of workloads and flow rates for which ground testing is nominally performed. Three subjects were tested in each suit. In all but one case, each subject performed the test twice. Suit pressure was maintained at 4.3 psid. Subjects wore the suit while resting, performing arm ergometry, and walking on a treadmill to generate metabolic workloads of about 500 to 3000 BTU/hr. Supply airflow was varied between 6, 5, and 4 actual cubic feet per minute (ACFM) at each workload. Subjects wore an oronasal mask with an open port in front of the mouth and were allowed to breathe freely. Oronasal ppCO2 was monitored in real time by gas analyzers with sampling tubes connected to the mask. Metabolic rate was calculated from the total CO2 production measured by an additional gas analyzer at the suit air outlet. Real-time metabolic rate was used to adjust the arm ergometer or treadmill workload to meet target metabolic rates. In both suits, inspired CO2 was affected mainly by the metabolic rate of the subject: increased metabolic rate significantly (P < 0.05) increased inspired ppCO2. Decreased air flow caused small increases in inspired ppCO2. The effect of flow was more evident at metabolic rates . 2000 BTU/hr. CO2 washout values of the EM-ACES were slightly but not significantly better than those of the REI suit. Regression equations were developed for each suit to predict the mean inspired ppCO2 as a function of metabolic rate and suit flow rate. This paper provides detailed descriptions of the test hardware, methodology, and results as well as implications for future ground testing in the REI-suit and EM-ACES.

Mitchell, Kathryn C.↗

Establishing Standardized Test Methods for Evaluating Space Suit Gloves

The Artemis space suit glove environmental protection garment (EPG) will be the first line of protection used to shield the crewmember’s hands from the environments encountered during extravehicular activity (EVA). As the Artemis missions will include more extreme environments than those experienced on the International Space Station, development, verification, and validation of gloves poses three key challenges. First, there are no standardized tests defined to evaluate the durability of space suit gloves for the extreme lunar environments, particularly the permanently shadowed regions. Second, there is insufficient data on state-of-the-art glove performance in a lunar environment from which to compare new designs. Third, current ISS glove Thermal Micrometeoroid Garment (TMG) fabrics are unlikely to be sufficient to meet Lunar requirements. It is therefore necessary to define tests to evaluate if gloves can meet new, challenging requirements. This paper focuses on the development of a test procedure to characterize lunar EVA glove fabrics using ASTM standardized test methods and the design and validation of a new standardized test procedure for comparing abrasion resistance between fabrics in lunar-like conditions. The results of testing on twelve candidate EVA glove fabrics are presented.

Robert J. Jones↗

Advanced Pressure Garment Space Suit Sizing Considerations

Fitting a space suit to a person could be considered an art form. Establishing a repeatable fitcheck process to accommodate the full anthropometric range of test subjects for a single suit design is a critical process to be able to prove suit functionality. Suited test subjects can have different preferences on how they fit inside a suit, and different suited test environments can lead to differences in certain suit sizing accommodations. Throughout this paper, the process of achieving an acceptable suit fit for test subjects will be discussed, along with sizing considerations for changes in suit design and test environments. Lessons learned from the Exploration Extravehicular Mobility Unit (xEMU) will be used to describe specific examples, along with key takeaways from additional NASA prototype mobility space suits. The suit fitcheck process starts with utilizing the anthropometric measurements of a test subject to evaluate their relation to the dimensions of space suit hardware in creating a predicted suit sizing configuration. From here, subjective comments and test team observations drive iterations to the suit sizing configuration to culminate in an acceptable suit fit for performance of further test evaluations. Understanding the relation of subjective comments to their impact on altering suit sizing is critical in establishing an acceptable suit fit.

spacesuit↗